On Mon, Jul 21, 2025 at 2:38 PM Japin Li <japi...@hotmail.com> wrote: > > > Hi, hackers, > > I was recently reviewing the KeepFileRestoredFromArchive() function and came > across a section that raised a question for me: > > /* > * Create .done file forcibly to prevent the restored segment from being > * archived again later. > */ > if (XLogArchiveMode != ARCHIVE_MODE_ALWAYS) > XLogArchiveForceDone(xlogfname); > else > XLogArchiveNotify(xlogfname); > > My understanding is that the WAL segment in this context has just been > restored from the archive. > > However, for archive_mode=always, the code calls XLogArchiveNotify(xlogfname), > which, if I understand correctly, signals the archiver to re-archive this > already-archived WAL segment. > > Is there a specific scenario or benefit I'm overlooking?
One possible scenario is when the archive directory used by restore_command is different from the one used by archive_command. For example, the primary and standby servers might each have their own separate archive directories, with archive_command configured to archive WAL files to their respective directories. Meanwhile, the standby’s restore_command might be set up to fetch WAL files from the primary’s archive directory. This kind of setup can be used when there’s no shared archive directory between the primary and standby. In such cases, even WAL files restored on the standby might need to be archived again. Regards, -- Fujii Masao
